长周期光纤光栅模式与耦合的研究  

Modes and Couplings of Long Period Fiber Grating

作　　者：何万迅[1] 施文康[1] 叶爱伦 高侃[2] 方祖捷[2] 

机构地区：[1]上海交通大学电子信息学院仪器系,上海200030 [2]中国科学院上海光学精密机械研究所,上海201800

出　　处：《光学学报》2003年第3期302-306,共5页Acta Optica Sinica

基　　金：上海市科技发展基金 (99JC14 0 0 4 )资助课题

摘　　要：长周期光纤光栅是在光纤纤芯中沿轴向形成折射率周期性调制的带阻型光纤器件。与光纤布拉格光栅不同 ,它表现为前向传播的纤芯基模与同向传播的各阶次包层模式在特定波长的耦合。研究了纤芯基模、包层模式(HE1l/EH1l)及其有效折射率随波长的变化 ,研究了纤芯基模与包层模式 (HE1l/EH1l)的耦合系数。研究表明 ,纤芯基模与一阶低次包层模式的有效折射率随波长增大而减小 ,纤芯基模与HE1l产生的耦合系数远大于与EH1l的耦合系数 ,并且包层模式次数较低时 ,耦合系数随次数的升高而增加。这与以前的研究结果有所不同。A long period fiber grating (LPFG) is a band-rejection fiber device with periodical refractive index modulation formed along the axis of the fiber core. Different with a fiber Bragg grating (FBG), it couples light from the forward-propagating fundamental core mode into co-propagating cladding modes at discrete wavelengths. Dependence of effective indices for fundamental core mode and cladding modes (HE1l/EH1l) upon wavelength, and the coupling constants between fundamental core mode and cladding modes (HE1l/EH1l) are studied. It is found that effective refractive indices for the core mode and cladding modes of LPFG both decrease with wavelength. Coupling constant formed with HE1l mode is much greater than that with EHU mode. Also coupling constants increase with the order of cladding modes at the lowest few ones. These differ with the conclusions drawn before.

关 键 词：纤维光学 长周期光纤光栅 模式耦合 有效拆射率 耦合系数 

分 类 号：TN929.11[电子电信—通信与信息系统]